Ignition in an internal combustion engine, takes place just prior to the piston reaching "top dead centre". Combustion takes place with considerable expansion of the mixture within the combustion chamber.
It is advantageous for combustion to take place at as high a pressure as possible. Engines are usually designed to have a compression ratio of 8:1 to 9:1. However as the piston is descending combustion is still taking place and accordingly, pressure within the combustion chamber is reduced from an optimum. This results in incomplete combustion of the fuel which in turn leads to loss of power and pollution problems.
Disclosed in International Application PCT/CA92/00522 is a piston rod and piston connection which addresses the above issue. The upper end of the piston rod is provided with raised portions which engage the underside of the piston crown. As the connecting rod rotates angularly, the piston is caused to move away from the other end of the connecting rod.
Similar such mechanisms are disclosed in U.S. Pat. Nos. 1,431,617, 4,515,441, 2,260,240 and 2,574,934.